Filament spool



FIG. 1 is a top perspective view of a design for a filament spool.

FIG. 2 is a bottom perspective view of the design.

FIG. 3 is a top view of the design.

FIG. 4 is a bottom view of the design.

FIG. 5 is a left side view of the design.

FIG. 6 is a right side view of the design.

FIG. 7 is a front view of the design; and,

FIG. 8 is a back view of the design.

The broken lines showing portions of the filament spool are for illustrative purposes only and form no part of the claimed design. 

CLAIM The ornamental design for a filament spool, as shown and described. 